Absolute colors and phase coefficients of trans-Neptunian objects: HV-HR and relative phase coefficients

TL;DR

This study constructs phase curves for a large sample of trans-Neptunian objects in V and R filters to analyze their physical properties, revealing a strong anticorrelation between color differences and phase coefficient differences.

Contribution

It provides new absolute magnitudes and phase coefficients for 114 TNOs, and identifies a significant anticorrelation between color and phase coefficient differences, enhancing understanding of surface properties.

Findings

Strong anticorrelation between H_V-H_R and Δβ.

New magnitudes for 35 TNOs in V and R filters.

Surface structure influences phase behavior more than composition or size.

Abstract

The trans-Neptunian objects (TNOs) are small Solar System bodies at large distances from the Sun. As such, their physical properties are difficult to measure. Accurate determination of their physical parameters is essential to model and theorize the actual composition and distribution of the population, and to improve our understanding of the formation and evolution of the Solar System. The objective of this work is to construct phase curves in two filters, $V$ and $R$, of a large TNO sample obtaining absolute magnitudes ($H$) and phase coefficients ($\beta$), and study possible relations between them and other physical parameters (orbital elements, sizes, and albedos). We used our own data, together with data from the literature, to create the phase curves assuming an overall linear trend. We obtained new magnitudes for 35 TNOs, 27 in the V filter and 35 in the R filter. These magnitudes, together with data from the literature, allowed us to obtain absolutes magnitudes, 114 in the V filter and 113 in the R filter, of which 106 have both. From the search for correlations we found a strong anticorrelation between $H_V-H_R$ and $\Delta \beta=\beta_V-\beta_R$, which is probably more related to surface structure than to composition or size of the objects.